Experimental Study Of Selective Catalytic Reduction (SCR) Of NO With Catalysts Of V₂O₅-WO₃-SiO₂/TiO₂ And Ag/Al₂O₃

Nitrogen oxides (NOx) are gaseous pollutants that contribute to the acid rain formation, the photochemical air pollution, and the depletion of the ozone layer. Other problems linked with the presence of nitrogen oxides in the atmosphere are health problems to humans, like bronchitis, pneumonia, and susceptibility to viral infections. The main sources of NOx emissions in the atmosphere from human activities are power plants, boilers, and vehicles' engines. Selective Catalytic Reduction (SCR) processes have been developed to convert the NOx to nitrogen and H₂0 and thus limit the environment pollution.With a review of chemistry and mechanism research of the selective catalytic reduction of NOx by ammonia, which include the mechanism of SCR reaction, SCR catalysts, SCR stoichiometry and kinetics research and further study in this field had been discussed.The experiments include the evaluation of catalysts V₂O₅-WO₃-SiO₂/TiO₂ and Ag/Al₂O₃ respectively using the reducing agent ammonia NH₃ and propenePorous ceramics carrier supporting V₂O₆-WO₃-Si0₂/Ti0₂ was used to study the selective catalytic reduction of NO with NH₃. The experiment was done in a fix-bed integral reactor and reaction temperature, contact time and injection quality of NH₃ all affect the SCR reaction. The result shows that the porous ceramics catalyst is active for NO removal. When T = 350 ℃ , contact time=0. 8 1. 0s, n (NH₃/N0) =1.25:1, the optimal NO conversion of above 90% could be achieved. Kinetics of SCR process on catalyst was studied and kinetic parameters have also been obtained.The ammonia slip, the corrosion of equipment, and the storage of ammonia are operational problems that are solved by replacing ammonia with hydrocarbons, which probably already exist in the inlet gas stream of DeNOx units. Therefore, we use ceramic cordierite honeycomb-supported Ag/Al₂O₃ monolithic catalyst for the selective catalytic reduction of NO with propene C₃H₆ as reducing agent. The experiments were investigated in a fix-bed integral reactor, eliminate the effect of diffusion and investigated the different Ag contents, 0₂ contents, temperature and S0₂. the experiments results show that a higher temperature can be achieved...